High active detergent particles for inclusion in concentrated detergent products can be made by various known processes. One method is dilute neutralization of the surfactant acid with caustic followed by drying to low moisture to make a concentrated paste which can be formed into high active particles.
Another way is to use a continuous neutralization system such as a continuous neutralization loop. Concentrated (about 50% solids) caustic and the surfactant acid can be separately added to a continuous neutralization loop, where neutralization takes place. The resulting low moisture surfactant paste from the loop can be cooled and made into high active detergent granules by, for example, extrusion.
The art discloses some ingredients which can be added to improve cold water dispersibility. For example, Japanese Patent 63-199797, Nakamura et al., laid open Aug. 18, 1988, describes a high density granular detergent composition to which a certain amount of water-soluble and crystalline salts are added to improve cold water dispersibility.
In European Patent Application 0 080 222, Barford, published June 6, 1983, the granular detergent compositions comprise a non-soap anionic surfactant and a water-soluble anionic polymer in intimate admixture and a water-soluble neutral or alkaline salt. The compositions exhibit an improved speed of solubility.
Cold water washing is addressed by U.S. Pat. No. 4,695,284, Hight, issued Sep. 22, 1987, which discloses built detergent particles comprising nonionic surfactant, saturated fatty acid builder salt and carrier material.
Japanese Patent 6222800 claims a solubility improvement by coating granular detergent particles with fine powders and regulating particle size.
It has heretofore been difficult to make high active alkyl sulfate particles which are dispersible under cool or cold water washing conditions.